We are working to make hubspot a good system for our marketing events, and the custom object really come in handy here. We have made a custom object called "Events" and associate the contacts, companies and deals related to our different events. This works in small scale because we have to do all association to custom objects manually, but we need the ability to associate custom objects via workflows to make it scalable and truly smart.
Lets give custom objects the credit it deserves by making it scalable.